Introduction

"A professional research astronomer does not merely appreciate the beauty and wonder of the objects in the sky. This is the daily challenge - to come to some sort of understanding of the basic underlying physics that gave rise to the universe and the objects in it. It is this challenge and the satisfaction gained by solving these puzzles that drew me to astronomy."

— Tereasa Brainerd, California Institute of Technology. Primary research of interest: the origin and evolution of structure in the universe.

A New Universe to Discover

When astronomer James Scotti was asked to photograph a newly discovered comet with the University of Arizona's 36-inch telescope, he was not prepared for the image that appeared on his computer screen. What he saw was not one comet but a chain of comets that looked like a string of pearls. "I was struck by the unique appearance of a train of individual [comet] nuclei all lined up in a row," Said Dr. Scotti. "I had never before seen such a unique image in a comet." In fact, nothing like it had been seen by other astronomers either. The pearls were the remnant of a comet that had come too close to Jupiter and broke into at least 21 fragments. Even more extraordinary, 18 months later these comet fragments, known collectively as Comet Shoemaker-Levy 9, would collide with Jupiter, providing astronomers the opportunity to study such an event for the first time!

The Magellan spacecraft had already mapped over 84 percent of the surface of Venus with its imaging radar when it revealed a surprising new feature: a narrow channel snaking its way 4,200 miles across the hellish surface. The channel is 55 miles longer than the Nile River, the longest river on Earth. Water could not have carved out this channel, because the planet's high surface pressure and temperature would have quickly transformed liquid water to vapor. Lava is one possibility, but to carve the narrow channel, it would have had to flow rapidly and with the consistency of paint. "The very existence of such a channel is a great puzzle," said Dr. Steve Saunders, project scientist for the Magellan mission. "If the long channel were carved by something flowing on the surface, the liquid must have had some unusual properties."

Astronomer C. Robert O'Dell of Rice University aimed NASA's Hubble Space Telescope at the rich star-forming region known as the Orion Nebula to study newborn stars. What he and his colleagues found instead were solar systems in the making. The images from the Space Telescope revealed stars so young they were still embedded in the disks of dust from which they formed. Dr. O'Dell calls these objects proplyds. "These disks are a missing link in our understanding of how planets like those in our solar system form," said Dr. O'Dell. "It is likely that many of these stars have planetary systems."

It is often said that astronomy is the oldest science, but in many respects it is also the newest science because year after year discoveries and new insights such as the ones above continually remake and revise our perspective of the universe. In the past two decades alone, astronomy has experienced a flurry of discoveries unprecedented in its history. Many of these discoveries sound more like science fiction than science fact: light echoes around exploding stars; gamma ray bursters; "great walls" of galaxies; voids in space; cosmic jets; gravitational lenses; Einstein rings. Such discoveries not only reveal a universe richer and more varied than had been suspected by previous generations, but pose bold, new challenges for scientists.

Modern astronomy is flourishing. Interplanetary spacecraft have observed eight of the nine planets in phenomenal detail, mapped and landed on the surfaces of the moon, Mars, and Venus, and returned the first close-up images of a comet nucleus and several asteroids. Orbiting observatories scrutinize star clusters, nebulae, the violent cores of galaxies, and distant quasars. Another orbiting spacecraft, the Cosmic Background Explorer, has mapped the faint background glow of energy that is believed to be the remnant radiation from the big bang 15 billion years ago.

Meanwhile, astronomers are using ground-based telescopes, equipped with the latest electronic light-gathering instruments, to measure the chemical composition of stars, the mass of galaxy clusters, and looking for planets around other stars. Future years will see an armada of new large telescopes brought to bear on some of the most important astronomical questions being asked today. How old are the oldest stars? How did the first galaxies form in the universe? Why is most of the mass in the universe not directly observable? What is the nature of this "dark matter?" Will the universe expand forever?

Of course, astronomers don't just use telescopes in their studies of the universe. In recent years, powerful supercomputers have been employed to, among other things, model cosmic jets and the environment around pulsars and black holes, simulate galaxy collisions, and devise better theories on how galaxies clustered into large-scale structures in the early universe.

Astronomers also study data gathered by physicists using particle accelerators. Key questions about the big bang and the nature of matter in the universe can only be answered by studying the behavior and forces of elementary particles and, perhaps, discovering new particles. Hence, in order to understand how the very large came to be, astronomers must learn what they can about the very small.

Preparation for a Career in Astronomy

You may have heard somewhere that astronomy is "hard" or difficult to grasp. This may seem to be the case because astronomers don't have laboratories like chemists, biologists, or paleontologists; they can't put stars in test tubes or galaxies in a centrifuge. Their "fossils" lie millions and even billions of light-years away. Most of the time, astronomers derive information from an analysis of the light or the motions of celestial bodies, a process that, to the uninitiated, may seem more like sorcery than science.

In fact, astronomy is a challenging science, but not because the universe is inaccessible in the conventional sense. Rather, astronomers must apply equal measures of analytic thinking and imagination, logic and intuition, to answer the most fundamental questions about the cosmos: What are stars and planets? How did they evolve? Why does the night sky look the way it does? Does life exist among the stars? How did the universe get here? How will it end? If astronomy seems a rigorous science, it's because the objective of astronomers is nothing less than to understand the nature of the universe. It takes a special person to pursue this objective; one who likes to challenge and be challenged.

High School

Decisions made in high school can have a big effect on a science career. Generally, students who take mathematics or science courses after the tenth grade have the best chance of successfully pursuing a science or engineering career. Although most colleges require at least one year of high school science and two years of high school mathematics, this minimum background is insufficient for students planning to major in science. A better approach is to complete math through pre-calculus in high school. This gives students who plan to major in astronomy or physics the necessary grounding in mathematics needed to start their science courses as soon as they begin college. Both chemistry and physics courses are also strongly recommended in high school as adequate preparation for the first year of college. Many entering students have taken advanced placement calculus and/or physics, though these courses are not required.

Students are also encouraged to get involved in high school science groups, state junior academies of science, and local amateur astronomy clubs. There are literally thousands of such organizations in the United States.

College

College undergraduates planning careers in astronomy must obtain a solid foundation in physics and mathematics. An astronomy major with a strong background in physics, or a physics major with some astronomy coursework, should have a sufficient foundation in physics and math to seek a graduate program in astronomy. Specifically, a student planning to go on to graduate school in astronomy should have had physics courses covering electricity and magnetism, atomic and nuclear physics, thermodynamics, statistical mechanics, and quantum theory. For some astronomy specialties, however, studies in geology or chemistry may be more appropriate.

Computer science, too, permeates all facets of astronomy today. In recent years, supercomputers have allowed astronomers to simulate processes that before were nearly impossible to study. A good grounding in computer science, therefore, will benefit prospective astronomers, especially those considering a specialty in theoretical astronomy.

In addition, a good scientist must also have the ability to read and write clearly and to communicate well with people, often across cultural boundaries. Do not neglect college courses in writing, the humanities, and the social sciences.

Graduate School

Most astronomy positions require a PhD degree, which can take five or six years of graduate work. This path enables the astronomer to do much independent work, which is what makes astronomy enjoyable: finding a problem and finding a way to solve it. Admission to graduate schools generally requires completing an undergraduate physics or astronomy/physics major with a B average or better and satisfactory performance on the Graduate Record Exam. Once admitted, the astronomy graduate students take advanced courses in astronomy and astrophysics while beginning to undertake some research. The specific courses depend on the requirements of the department and on the student's research interests. After the first two years of course work, the graduate program generally requires research projects to be conducted under the supervision of faculty members, culminating in a PhD dissertation.